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From: Will Deacon <will.deacon@arm.com>
To: Qian Cai <cai@lca.pw>
Cc: catalin.marinas@arm.com, linux-kernel@vger.kernel.org,
	rostedt@goodmis.org, mingo@redhat.com,
	kasan-dev@googlegroups.com, andreyknvl@google.com,
	aryabinin@virtuozzo.com, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] trace: skip hwasan
Date: Mon, 18 Feb 2019 10:43:59 +0000	[thread overview]
Message-ID: <20190218104359.GB10743@fuggles.cambridge.arm.com> (raw)
In-Reply-To: <20190217043434.46233-1-cai@lca.pw>

On Sat, Feb 16, 2019 at 11:34:34PM -0500, Qian Cai wrote:
> Enabling function tracer with CONFIG_KASAN_SW_TAGS=y (hwasan) tracer
> causes the whole system frozen on ThunderX2 systems with 256 CPUs,
> because there is a burst of too much pointer access, and then KASAN will
> dereference each byte of the shadow address for the tag checking which
> will kill all the CPUs.
> 
> Signed-off-by: Qian Cai <cai@lca.pw>
> ---
>  kernel/trace/Makefile | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
> index c2b2148bb1d2..fdd547a68385 100644
> --- a/kernel/trace/Makefile
> +++ b/kernel/trace/Makefile
> @@ -28,6 +28,11 @@ ifdef CONFIG_GCOV_PROFILE_FTRACE
>  GCOV_PROFILE := y
>  endif
>  
> +# Too much pointer access will kill hwasan.
> +ifdef CONFIG_KASAN_SW_TAGS
> +KASAN_SANITIZE := n
> +endif

I don't maintain this file, but I think that my comments on your related
patch are relevant here as well:

https://lkml.org/lkml/2019/2/18/223

Will

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  parent reply	other threads:[~2019-02-18 10:44 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-17  4:34 [PATCH] trace: skip hwasan Qian Cai
2019-02-17  7:30 ` Dmitry Vyukov
2019-02-18 13:27   ` Qian Cai
2019-02-18 13:56     ` Dmitry Vyukov
2019-02-18 13:59       ` Will Deacon
2019-02-21 14:19         ` James Morse
2019-02-18 10:43 ` Will Deacon [this message]
2019-02-18 15:25 ` Andrey Konovalov
2019-02-18 15:53   ` Qian Cai
2019-02-18 15:56     ` Andrey Konovalov
2019-02-18 17:23       ` Steven Rostedt

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